Embodiments of the present invention relate to a rotary centrifuge for centrifuging samples.
A rotary centrifuge rotates sample containers containing samples to apply centrifugal forces to the samples. The sample may be, for example, a fluid to which centrifugal forces are applied to separate, for example, components of the fluid that have different densities. Typically, the rotary centrifuge has a rotatable hub to receive pivoting buckets and a drive mechanism to rotate the hub. The pivoting buckets each comprise a receptacle to receive a sample container and a closing cap. A trunnion attached to the bucket has pivot pins that seat in corresponding holes in the hub of the centrifuge to allow the bucket to pivot as the hub is rotated. Trunnion springs may also be used to allow the buckets in their pivoted position to be displaced radially outwardly at high rotational velocities until the buckets are supported by a circumferential surface of the hub to reduce the centrifugal load on the bucket itself while still allowing the centrifugal forces to still operate on the sample in the bucket.
However, such conventional trunnion and bucket systems have several problems. One problem is that the interfaces and joints of conventional trunnion and bucket systems are often not as strong as desirable. For example, the joint between the trunnion and pivot pins can weaken at high rotational speeds. In addition, the trunnion spring mechanism that allows the bucket to slide radially outwardly at high speeds is also difficult to manufacture with sufficient strength and resilience. Also, when multiple components are assembled to make a trunnion and bucket system, such systems are more susceptible to failure from mis-assembly or misalignment of the different components. Another problem arises when the cap is not properly attached to the receptacle of the bucket. During operation of the centrifuge, vibrations may cause the cap to rotate and loosen off the receptacle, causing the sample held inside to be damaged.
Thus, it is desirable to have a bucket, trunnion, and trunnion spring, that is strong, resilient and provides improved ease of assembly and manufacture. It is also desirable to have a receptacle cap that remains securely attached to the receptacle during operation of the centrifuge. It is further desirable for the cap to be easily attached to and removed from the receptacle.
A bucket is capable of holding a sample container in a rotary centrifuge. The bucket comprises (a) a receptacle to receive the sample container; and (b) a trunnion joined to the receptacle, the trunnion comprising: (i) a plurality of cutouts that each define a flexible span; and (ii) pivot pins to allow the bucket to pivot under the application of a centrifugal force generated by the rotary centrifuge.
A bucket capable of holding a sample container in a rotary centrifuge, the rotary centrifuge comprising an external seat, and the bucket comprising:
(a) a receptacle to receive the sample container, the receptacle comprising a seating surface; and
(b) a trunnion joined to the receptacle, the trunnion comprising:
(i) a plurality of cutouts that each define a flexible span that is sufficiently flexible to flex under application of a centrifugal force generated by the rotary centrifuge to allow the seating surface of the receptacle to seat against the external seat of the rotary centrifuge whereby the centrifugal force applied on the pivot pins may be reduced; and
(ii) pivot pins to allow the bucket to pivot under the application of the centrifugal force.
A bucket capable of holding a sample container in a rotary centrifuge, the bucket comprising:
(a) a receptacle to receive the sample container, the receptacle comprising an open end having an internal surface with a groove, the groove having an opening, an end, and a width that decreases in size from the opening to the end;
(b) a cap capable of closing the open end of the receptacle, the cap comprising pegs that are sized to fit in the groove; and
(c) a trunnion comprising a pair of pivot pins to allow the bucket to pivot under the application of a centrifugal force generated by the rotary centrifuge.
A bucket capable of holding a sample container in a rotary centrifuge, the bucket comprising:
(a) a receptacle to receive the sample container, the receptacle comprising an open end having an internal surface with a groove therein, the groove having an opening, an end, and a width that decreases from the opening to the end;
(b) a cap capable of closing the open end of the receptacle, the cap comprising pegs that are sized to fit in the groove; and
(c) a trunnion comprising:
(i) a plurality of cutouts that each define a flexible span that is sufficiently thin to flex under application of a centrifugal force generated by the rotary centrifuge; and
(ii) a pair of pivot pins to allow the bucket to pivot under the application of the centrifugal force.